Problem: Solve for $x$ and $y$ using substitution. ${-6x-4y = 10}$ ${y = -2x-6}$
Explanation: Since $y$ has already been solved for, substitute $-2x-6$ for $y$ in the first equation. ${-6x - 4}{(-2x-6)}{= 10}$ Simplify and solve for $x$ $-6x+8x + 24 = 10$ $2x+24 = 10$ $2x+24{-24} = 10{-24}$ $2x = -14$ $\dfrac{2x}{{2}} = \dfrac{-14}{{2}}$ ${x = -7}$ Now that you know ${x = -7}$ , plug it back into $\thinspace {y = -2x-6}\thinspace$ to find $y$ ${y = -2}{(-7)}{ - 6}$ $y = 14 - 6$ $y = 8$ You can also plug ${x = -7}$ into $\thinspace {-6x-4y = 10}\thinspace$ and get the same answer for $y$ : ${-6}{(-7)}{ - 4y = 10}$ ${y = 8}$